Looks like a red chilli. In fact, Naples' traditional good luck charm is a horn. This is supposed to ward off the "evil eye". The lucky charm must be stiff, hollow, crooked and pointed to be effective, so they say. And you have to Cornicello or Curniciello (as it is correctly called in Neapolitan) on being given as a present...

The writer Matilde Serão (*1858 †1927) defines the croissant as the "incurable disease of Neapolitans": before leaving the house, rub the curniciello (Neapolitan)before a first date, an important doctor's appointment and before important business meetings anyway.